patroni.dcs.kubernetes module¶
- class patroni.dcs.kubernetes.CoreV1ApiProxy(use_endpoints: Optional[bool] = False, bypass_api_service: Optional[bool] = False)¶
Bases:
object
Proxy class to work with k8s_client.CoreV1Api() object
- _DEFAULT_RETRIABLE_HTTP_CODES = frozenset({500, 503, 504})¶
- class patroni.dcs.kubernetes.K8sClient¶
Bases:
object
- class ApiClient(bypass_api_service: Optional[bool] = False)¶
Bases:
object
- _API_URL_PREFIX = '/api/v1/namespaces/'¶
- _calculate_timeouts(api_servers: int, timeout: Optional[float] = None) Tuple[int, float, int] ¶
Calculate a request timeout and number of retries per single K8s API server node. In case if the timeout per node is too small (less than one second) we will reduce the number of nodes. For the cluster with only one API server node we will try to do 1 retry. No retries for clusters with 2 or more API server nodes. We better rely on switching to a different node.
- _do_http_request(retry: Optional[Retry], api_servers_cache: List[str], method: str, path: str, **kwargs: Any) HTTPResponse ¶
- static _handle_server_response(response: HTTPResponse, _preload_content: bool) Union[HTTPResponse, K8sObject] ¶
- call_api(method: str, path: str, headers: Optional[Dict[str, str]] = None, body: Optional[Any] = None, _retry: Optional[Retry] = None, _preload_content: bool = True, _request_timeout: Optional[float] = None, **kwargs: Any) Union[HTTPResponse, K8sObject] ¶
- class patroni.dcs.kubernetes.K8sConfig¶
Bases:
object
- static _get_by_name(config: Dict[str, List[Dict[str, Any]]], section: str, name: str) Optional[Dict[str, Any]] ¶
- _pool_config_from_file_or_data(config: Dict[str, str], file_key_name: str, pool_key_name: str) None ¶
- exception patroni.dcs.kubernetes.K8sConnectionFailed¶
Bases:
K8sException
- class patroni.dcs.kubernetes.Kubernetes(config: Dict[str, Any])¶
Bases:
AbstractDCS
- _CITUS_LABEL = 'citus-group'¶
- __init__(config: Dict[str, Any]) None ¶
Prepare DCS paths, Citus group ID, initial values for state information and processing dependencies.
- Variables:
config –
dict
, reference to config section of selected DCS. i.e.:zookeeper
for zookeeper,etcd
for etcd, etc…
- __load_cluster(group: Optional[str], loader: Callable[[Dict[str, Any]], Union[Cluster, Dict[int, Cluster]]]) Union[Cluster, Dict[int, Cluster]] ¶
- _abc_impl = <_abc._abc_data object>¶
- _citus_cluster_loader(path: Dict[str, Any]) Dict[int, Cluster] ¶
Load and build all Patroni clusters from a single Citus cluster.
- Parameters:
path – the path in DCS where to load Cluster(s) from.
- Returns:
all Citus groups as
dict
, with group IDs as keys andCluster
objects as values or aCluster
object representing the coordinator with filled Cluster.workers attribute.
- _cluster_loader(path: Dict[str, Any]) Cluster ¶
Load and build the
Cluster
object from DCS, which represents a single Patroni or Citus cluster.- Parameters:
path – the path in DCS where to load Cluster(s) from.
- Returns:
Cluster
instance.
- _load_cluster(path: str, loader: Callable[[Any], Union[Cluster, Dict[int, Cluster]]]) Union[Cluster, Dict[int, Cluster]] ¶
Main abstract method that implements the loading of
Cluster
instance.Note
Internally this method should call the loader method that will build
Cluster
object which represents current state and topology of the cluster in DCS. This method supposed to be called only by theget_cluster()
method.- Parameters:
path – the path in DCS where to load Cluster(s) from.
loader – one of
_cluster_loader()
or_citus_cluster_loader()
.
- Raise:
DCSError
in case of communication problems with DCS. If the current node was running as a primary and exception raised, instance would be demoted.
- _patch_or_create(name: str, annotations: Dict[str, Any], resource_version: Optional[str] = None, patch: bool = False, retry: Optional[Callable[[...], Any]] = None, ips: Optional[List[str]] = None) K8sObject ¶
Patch or create K8s object, Endpoint or ConfigMap.
- Parameters:
name – the name of the object.
annotations – mapping of annotations that we want to create/update.
resource_version – object should be updated only if the
resource_version
matches provided value.patch –
True
if we know in advance that the object already exists and we should patch it.retry – a callable that will take care of retries
ips –
IP address that we want to put to the subsets of the endpoint. Could have following values:
None
- when we don’t need to touch subset;[]
- to set subsets to the empty list, whendelete_leader()
method is called;['ip.add.re.ss']
- when we want to make sure that the subsets of the leader endpoint contains the IP address of the leader, that we get from thekubernetes.pod_ip
;['']
- when we want to make sure that the subsets of the leader endpoint contains the IP address of the leader, butkubernetes.pod_ip
configuration is missing. In this case we will try to take the IP address of the Pod which name matchesname
from the config file.
- Returns:
the new
V1Endpoints
orV1ConfigMap
object, that was created or updated.
- _update_leader_with_retry(annotations: Dict[str, Any], resource_version: Optional[str], ips: List[str]) bool ¶
- attempt_to_acquire_leader() bool ¶
Attempt to acquire leader lock.
Note
This method should create
/leader
key with the value_name
.The key must be created atomically. In case the key already exists it should not be overwritten and
False
must be returned.If key creation fails due to DCS not being accessible or because it is not able to process requests (hopefully temporary), the
DCSError
exception should be raised.- Returns:
True
if key has been created successfully.
- cancel_initialization() bool ¶
Removes the
initialize
key for a cluster.- Returns:
True
if successfully committed to DCS.
- client_path(path: str) str ¶
Construct the absolute key name from appropriate parts for the DCS type.
- Parameters:
path – The key name within the current Patroni cluster.
- Returns:
absolute key name for the current Patroni cluster.
- delete_cluster(*args: Any, **kwargs: Any) Any ¶
Delete cluster from DCS.
- Returns:
True
if successfully committed to DCS.
- delete_leader(leader: Optional[Leader], last_lsn: Optional[int] = None) bool ¶
Update
optime/leader
and voluntarily remove leader key from DCS.This method should remove leader key if current instance is the leader.
- Parameters:
leader –
Leader
object with information about the leader.last_lsn – latest checkpoint location in bytes.
- Returns:
boolean result of called abstract
_delete_leader()
.
- delete_sync_state(version: Optional[str] = None) bool ¶
Patch annotations of $SCOPE-sync Endpoint or ConfigMap with empty values.
Effectively it removes “leader” and “sync_standby” annotations from the object. :param version: last known resource_version for conditional update of the object :returns: True if “delete” was successful
- get_citus_coordinator() Optional[Cluster] ¶
Load the Patroni cluster for the Citus Coordinator.
Note
This method is only executed on the worker nodes (
group!=0
) to find the coordinator.- Returns:
Select
Cluster
instance associated with the Citus Coordinator group ID.
- initialize(create_new: bool = True, sysid: str = '') bool ¶
Race for cluster initialization.
This method should atomically create
initialize
key and returnTrue
, otherwise it should returnFalse
.- Parameters:
create_new –
False
if the key should already exist (in the case we are setting the system_id).sysid – PostgreSQL cluster system identifier, if specified, is written to the key.
- Returns:
True
if key has been created successfully.
- manual_failover(leader: Optional[str], candidate: Optional[str], scheduled_at: Optional[datetime] = None, version: Optional[str] = None) bool ¶
Prepare dictionary with given values and set
/failover
key in DCS.- Parameters:
leader – value to set for
leader
.candidate – value to set for
member
.scheduled_at – value converted to ISO date format for
scheduled_at
.version – for conditional update of the key/object.
- Returns:
True
if successfully committed to DCS.
- patch_or_create_config(annotations: Dict[str, Any], resource_version: Optional[str] = None, patch: bool = False, retry: bool = True) bool ¶
- reload_config(config: Union[Config, Dict[str, Any]]) None ¶
Handles dynamic config changes.
Either cause by changes in the local configuration file + SIGHUP or by changes of dynamic configuration
- set_config_value(value: str, version: Optional[str] = None) bool ¶
Create or update
/config
key in DCS.- Parameters:
value – new value to set in the
config
key.version – for conditional update of the key/object.
- Returns:
True
if successfully committed to DCS.
- set_history_value(value: str) bool ¶
Set value for
history
in DCS.- Parameters:
value – new value of
history
key/object.- Returns:
True
if successfully committed to DCS.
- static subsets_changed(last_observed_subsets: List[K8sObject], ip: str, ports: List[K8sObject]) bool ¶
>>> ip = '1.2.3.4' >>> a = [k8s_client.V1EndpointAddress(ip=ip)] >>> s = [k8s_client.V1EndpointSubset(addresses=a)] >>> Kubernetes.subsets_changed(s, '1.2.3.5', []) True >>> s = [k8s_client.V1EndpointSubset(addresses=a, ports=[k8s_client.V1EndpointPort(protocol='TCP', port=1)])] >>> Kubernetes.subsets_changed(s, '1.2.3.4', [k8s_client.V1EndpointPort(port=5432)]) True >>> p1 = k8s_client.V1EndpointPort(name='port1', port=1) >>> p2 = k8s_client.V1EndpointPort(name='port2', port=2) >>> p3 = k8s_client.V1EndpointPort(name='port3', port=3) >>> s = [k8s_client.V1EndpointSubset(addresses=a, ports=[p1, p2])] >>> Kubernetes.subsets_changed(s, ip, [p2, p3]) True >>> s2 = [k8s_client.V1EndpointSubset(addresses=a, ports=[p2, p1])] >>> Kubernetes.subsets_changed(s, ip, [p2, p1]) False
- take_leader() bool ¶
Establish a new leader in DCS.
Note
This method should create leader key with value of
_name
andttl
ofttl
.Since it could be called only on initial cluster bootstrap it could create this key regardless, overwriting the key if necessary.
- Returns:
True
if successfully committed to DCS.
- touch_member(*args: Any, **kwargs: Any) Any ¶
Update member key in DCS.
Note
This method should create or update key with the name with
/members/
+_name
and the value of data in a given DCS.- Parameters:
data – information about an instance (including connection strings).
- Returns:
True
if successfully committed to DCS.
- update_leader(leader: Leader, last_lsn: Optional[int], slots: Optional[Dict[str, int]] = None, failsafe: Optional[Dict[str, str]] = None) bool ¶
Update
leader
key (or session) ttl and optime/leader.- Parameters:
leader –
Leader
object with information about the leader.last_lsn – absolute WAL LSN in bytes.
slots – dictionary with permanent slots
confirmed_flush_lsn
.failsafe – if defined dictionary passed to
write_failsafe()
.
- Returns:
True
ifleader
key (or session) has been updated successfully.
- watch(leader_version: Optional[str], timeout: float) bool ¶
Sleep if the current node is a leader, otherwise, watch for changes of leader key with a given timeout.
- Parameters:
leader_version – version of a leader key.
timeout – timeout in seconds.
- Returns:
if
True
this will reschedule the next run of the HA cycle.
- write_leader_optime(last_lsn: int) None ¶
Write value for WAL LSN to
optime
annotation of the leader object.- Parameters:
last_lsn – absolute WAL LSN in bytes.
- write_sync_state(leader: Optional[str], sync_standby: Optional[Collection[str]], version: Optional[str] = None) Optional[SyncState] ¶
Prepare and write annotations to $SCOPE-sync Endpoint or ConfigMap.
- Parameters:
leader – name of the leader node that manages /sync key
sync_standby – collection of currently known synchronous standby node names
version – last known resource_version for conditional update of the object
- Returns:
the new
SyncState
object or None
- exception patroni.dcs.kubernetes.KubernetesRetriableException(orig: ApiException)¶
Bases:
ApiException
- __init__(orig: ApiException) None ¶
- class patroni.dcs.kubernetes.ObjectCache(dcs: Kubernetes, func: Callable[[...], Any], retry: Retry, condition: Condition, name: Optional[str] = None)¶
Bases:
Thread
- __init__(dcs: Kubernetes, func: Callable[[...], Any], retry: Retry, condition: Condition, name: Optional[str] = None) None ¶
This constructor should always be called with keyword arguments. Arguments are:
group should be None; reserved for future extension when a ThreadGroup class is implemented.
target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.
name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number.
args is a list or tuple of arguments for the target invocation. Defaults to ().
kwargs is a dictionary of keyword arguments for the target invocation. Defaults to {}.
If a subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing anything else to the thread.
- run() None ¶
Method representing the thread’s activity.
You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.